typedef struct pm_req {


         char *physpath;     /* physical path of device  */


                             /* to configure. See libdevinfo(3LIB) */


         int  component;     /* device component   */


         int  value;         /* power level, threshold value, or count */


         void *data;         /* command-dependent variable-sized data */


         size_t  datasize;   /* size of data buffer */


     } pm_req_t;

Pointer to the physical path of a device. See libdevinfo(3LIB). For example, for the device /devices/pseudo/pm@0:pm the physpath value would be /pseudo/pm@0.

Non-negative integer specifying which component is being configured. The numbering starts at zero.

Non-negative integer specifying the threshold value in seconds or the desired power level, or the number of levels being specified.

Pointer to a buffer which contains or receives variable-sized data, such as the name of a device upon which this device has a dependency.

Size of the data buffer.

The device named by physpath is disabled from being power managed by the framework. The caller will power manage the device directly using the PM_DIRECT_NOTIFY, PM_GET_TIME_IDLE and PM_GET_CURRENT_POWER, PM_GET_FULL_POWER and PM_SET_CURRENT_POWER commands. If the device needs to have its power level changed either because its driver calls pm_raise_power(9F), pm_lower_power(9F), or pm_power_has_changed(9F) or because the device is the parent of another device that is changing power level or a device that this device depends on is changing power level, then the power level change of the device will be blocked and the caller will be notified as described below for the PM_DIRECT_NOTIFY command.

Error codes:

EBUSY

EPERM

The device named by physpath (which must have been the target of a PM_DIRECT_PM command) is re-enabled for Power Management by the framework.

Error codes:

EINVAL

These commands allow the process that is directly power managing a device to be notified of events that could change the power level of the device. When such an event occurs, this command returns information about the event.

arg (see ioctl(2)) points to a structure of type pm_state_change defined in <sys/pm.h>:

typedef struct  pm_state_change {


   char   *physpath;    /* device which has changed state */


   int     component;   /* which component changed state */
#if defined(_BIG_ENDIAN)
	ushort_t flags;      /* PSC_EVENT_LOST, PSC_ALL_LOWEST */
	ushort_t event;      /* type of event */
#else
	ushort_t event;      /* type of event *
	ushort_t flags;      /* PSC_EVENT_LOST, PSC_ALL_LOWEST */
#endif
	time_t  timestamp;   /* time of state change */+
	int     old_level;    /* power level changing from */
	int    new_level;   /* power level changing to */
	size_t  size;        /* size of buffer physpath points to */
} pm_state_change_t;

When an event occurs, the struct pointed to by arg is filled in. If the event type is PSC_PENDING_CHANGE, then the information in the rest of the struct describes an action that the framework would have taken if the device were not directly power managed by the caller. The caller is responsible for completing the indicated level changes using PM_SET_CURRENT_POWER below.

An event type of PSC_HAS_CHANGED indicates that the driver for the directly power managed device has called pm_power_has_changed(9F) due to the device changing power on its own. It is provided to allow the caller to track the power state of the device.

The system keeps events in a circular buffer. If the buffer overflow, the oldest events are lost and when the event that next follows a lost event is retrieved it will have PSC_EVENT_LOST set in flags.

PM_DIRECT_NOTIFY returns EWOULDBLOCK if no event is pending, and PM_DIRECT_NOTIFY_WAIT blocks until an event is available.

pm also supports the poll(2) interface. When an event is pending a poll(2) call that includes a file descriptor for /dev/pm and that has POLLIN or POLLRDNORM set in its event mask will return.

Component component of the device named by physpath (which must contain the physical path of a device against which the process has issued a PM_DIRECT_PM command) is set to power level value. If all components of the device named by physpath were at level 0, value is non-zero and some device has a dependency on this device, then all components of that device will be brought to full power before this command returns. Similarly, if the parent of the target device is powered off, then it will be brought up as needed before this command returns. When PM_SET_CURRENT_POWER is issued against a device, the resulting power change is included in the event list for PM_DIRECT_NOTIFY.

Error codes:

EINVAL

EIO

EPERM

The highest supported power level of component component of the device named by physpath is returned.

The current power level of component component of the device named by physpath is returned.

Error codes:

EAGAIN

PM_GET_TIME_IDLE returns the number of seconds that component component of the device named by physpath has been idle. If the device is not idle, then 0 is returned.

Note that because the state of the device may change between the time the process issues the PM_GET_TIME_IDLE command and the time the process issues a PM_SET_CURRENT_POWER command to reduce the power level of an idle component, the process must be prepared to deal with a PM_SET_CURRENT_POWER command returning failure because the driver has rejected the command as inappropriate because the device component has become busy. This can be differentiated from other types of failures by issuing the PM_GET_TIME_IDLE command again to see if the component has become busy.